DESCRIPTION: Articular cartilage functions as a load-bearing, low-friction, wear-resistant padding in joints. Osteoarthritis is a joint disease that often involve occurrence of cartilage defects (local loss of cartilage), which can enlarge if left untreated. Therefore, treatment strategies have been proposed to either restore cartilage or prevent further degeneration. Most of such strategies are biological in nature, aiming to recruit or embed cells that could regenerate cartilage. However, a biomechanical basis for defect progression or repair has not been explored in detail. While it seems likely that a joint containing a cartilage defect would have diminished capacity to bear load and to provide a low-friction surface, such biomechanical sequelae have been neither assessed in detail, nor considered as the targets of cartilage repair strategies. Therefore, this proposal seeks [unreadable] to 1) determine the effects of focal defects on cartilage load-bearing and friction, and 2) establish [unreadable] biomechanical concepts for effective repair that can be combined with existing methods. Also, MRI-based methods to assess effects of cartilage defects on joint function will be developed. Achievement of the project aims will advance the understanding of cartilage degeneration in arthritis, and provide targets for diagnosis and treatment of cartilage defects. [unreadable] [unreadable] [unreadable] [unreadable]